Frank Steegmans

An end to end QoS discovery architecture embedded in a TINA based multimedia platform

In this paper we envisage the issue of quality of service (QoS) management for multimedia services as an end to end QoS discovery problem. With this perception as a basis, we designed and implemented a layered QoS management architecture which handles QoS from the users perspective, as well as from the end systems and the networks perspective. The architecture is decomposed into three layers. First there is the QoS specification, presentation and parameterization layer at which an end user is able to specify his/her QoS requirements in a comprehensible and qualitative way, and at which these QoS requirements are translated into parameterized terminal capabilities. Secondly, there is the QoS matching and negotiation layer at which the parameterized QoS capabilities of different terminal end systems are marched and compared in order to search for a QoS equilibrium. Finally, there is the QoS implementation layer which implements the resolved QoS equilibrium in the network and in the terminals. This generic architecture, which allows a de-abstraction of user defined QoS, has been implemented in the context of a CORBA based TINA platform.

A generic architecture for management and control of end-to-end quality of service over multiple domains

Currently, service providers and network operators are exploring new business opportunities that can be found in offering packages of advanced highly customized services to both residential and corporate subscribers. The semantics of these services will be more sophisticated, their access will be better controlled, their usage will be more flexible in time (scheduled) and space (mobile access), and their delivery will be possible with different grades of Quality of Service (QoS). Multimedia services such as video conferencing, distance learning, tele surgery, or dynamic and scheduled trunk provisioning, subject to certain Subject Level Agreements (e.g. corporate VPNs), are just a few examples of services with higher semantics. Although these services could have a high market potential, their implementation and delivery are hampered by the lack of an efficient, flexible and integrated network and service management system. Particularly, in the network management domain we encounter the following three problems. First, the setup of multimedia streams with end-to-end QoS over multiple administrative business domains is impossible without adequate federating mechanisms between network management systems. Secondly, dynamic and flexible interworking mechanisms between different technology domains is ubiquitous for the automatic provisioning of trails over a set of heterogeneous networked systems (e.g. from ATM in the access to IP in the core, from MPLS to DWDM, or from Frame Relay to ATM). Third, management of end-to-end QoS is not only a matter of network QoS. Management of QoS in end terminals and end devices or at a web server is an integral part of the global QoS delivery process. The Telecommunications Information Networking Architecture (TINA) has defined a distributed and integrated computational platform for the management and delivery of QoS based services. This paper starts from a state of the art TINA system and elaborates potential enhancements and extensions in order to bring a solution for each of the three previous issues.

Specification and development of a multimedia conferencing call model using distributed object oriented techniques

This paper reports on the specification and development of an advanced, feature rich call handling mechanism. The conferencing call model, referred to as the service session graph, is heavily influenced by, and has significantly contributed to, the TINA service architecture informational viewpoint. It is shown that two new features of the model, implicit stream binding and control mechanisms, allow telecom services to incorporate advanced conferencing features in a very efficient way. A number of implementations are described, where the call model is extended with a series of end-user services and runs on top of ATM networks.

Implementation of Hidden Concurrency in CORBA Clients

This paper reports on the introduction of concurrency at the client side, as an engineering solution to improve performance. It is shown that, by combining a wait-by-necessity principle, where the calling process only blocks when a return value of a function call is needed, with the handle concept, used to control the access to an object, hidden concurrency can be introduced into CORBA-based client components. Concurrency is achieved by splitting sequential calls to servers through the creation of dedicated threads. Hidden signifies the fact that the split is hidden for the client code by including the thread creation in the serverStub, while the synchronisation needed at some point in the client process is done through the handle mechanism combined with the wait-by-necessity principle. The introduction of this kind of concurrency can be done transparently from the client and server application code. The principle of hidden concurrency through the introduction of multiple threads at the calling side has been contrasted with the single thread scenario through an example, which takes on the TINA (Telecommunication Information Networking Architecture) Connection Management Architecture as a particular case study.

Dynamically configurable protocol stacks

This paper presents a generic architecture for multimedia terminals with respect to the management and implementation of dynamic and programmable protocol stacks. This architecture is built around the combination of CORBA based management components and real-time multimedia data processing engines. The management objects export a set of easily usable interfaces, which allow cascading and configuring the engines in such a way that they terminate multimedia network connections with the desired protocol stack. Terminal software components, which are designed according to existing multimedia delivery standards (such as TINA or H.323) can be easily integrated with these CORBA components in order to introduce dynamic programmable multimedia endpoints in the terminal(s).